The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum

Astronomy & Astrophysics, Jul 2014

Context. Knowledge of the abundance distribution of star forming regions and young clusters is critical to investigate a variety of issues, from triggered star formation and chemical enrichment by nearby supernova explosions to the ability to form planetary systems. In spite of this, detailed abundance studies are currently available for relatively few regions.Aims. In this context, we present the analysis of the metallicity of the gamma Velorum cluster, based on the products distributed in the first internal release of the Gaia-ESO Survey.Methods. The gamma Velorum candidate members have been observed with FLAMES, using both UVES and Giraffe, depending on the target brightness and spectral type. In order to derive a solid metallicity determination for the cluster, membership of the observed stars must be first assessed. To this aim, we use several membership criteria including radial velocities, surface gravity estimates, and the detection of the photospheric lithium line.Results. Out of the 80 targets observed with UVES, we identify 14 high-probability members. We find that the metallicity of the cluster is slightly subsolar, with a mean [ Fe/H ] = −0.057 ± 0.018 dex. Although J08095427-4721419 is one of the high-probability members, its metallicity is significantly larger than the cluster average. We speculate about its origin as the result of recent accretion episodes of rocky bodies of ~60 M⊕ hydrogen-depleted material from the circumstellar disk.

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The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum

A&A The Gaia -ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum , L. Spina 11 12 S. Randich 12 F. Palla 12 G. G. Sacco 12 L. Magrini 12 E. Franciosini 12 L. Morbidelli 12 L. Prisinzano 9 E. J. Alfaro 17 K. Biazzo 16 A. Frasca 16 J. I. González Hernández 14 15 S. G. Sousa 18 19 V. Adibekyan 19 E. Delgado-Mena 19 D. Montes 13 H. Tabernero 13 A. Klutsch 16 G. Gilmore 7 S. Feltzing 8 R. D. Jeffries 5 G. Micela 9 A. Vallenari 6 T. Bensby 7 A. Bragaglia 3 E. Flaccomio 5 S. Koposov 13 A. C. Lanzafame 4 E. Pancino 1 3 A. Recio-Blanco 2 R. Smiljanic 0 10 M. T. Costado 17 F. Damiani 9 V. Hill 2 A. Hourihane 13 P. Jofré 13 P. de Laverny 2 T. Masseron 7 C. Worley 7 0 Department for Astrophysics, Nicolaus Copernicus Astronomical Center , ul. Rabian ́ska 8, 87-100 Torun ́ , Poland 1 ASI Science Data Center , via del Politecnico SNC, 00133 Roma , Italy 2 Université de Nice Sophia Antipolis , CNRS, Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 4 , France 3 INAF - Osservatorio Astronomico di Bologna , via Ranzani 1, 40127 Bologna , Italy 4 Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Universitá di Catania , via S. Sofia 78, 95123 Catania , Italy 5 Astrophysics Group, Research Institute for the Environment, Physical Sciences and Applied Mathematics, Keele University , Keele, Staffordshire ST5 5BG , UK 6 INAF - Padova Observatory , Vicolo dell'Osservatorio 5, 35122 Padova , Italy 7 Institute of Astronomy, University of Cambridge , Madingley Road, Cambridge CB3 0HA , UK 8 Lund Observatory, Department of Astronomy and Theoretical Physics , Box 43, 221 00 Lund , Sweden 9 INAF - Osservatorio Astronomico di Palermo , Piazza del Parlamento 1, 90134 Palermo , Italy 10 European Southern Observatory , Karl-Schwarzschild-Str. 2, 85748 Garching bei München , Germany 11 Università degli Studi di Firenze, Dipartimento di Fisica e Astrofisica, Sezione di Astronomia, Largo E. Fermi , 2, 50125 Firenze , Italy 12 INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi , 5, 50125 Firenze , Italy 13 Departamento de Astrofisica, Universidad Complutense de Madrid (UCM) , 28040 Madrid , Spain 14 Depto. Astrofisica, Universidad de La Laguna (ULL) , 38206 La Laguna, Tenerife , Spain 15 Instituto de Astrofisica de Canarias (IAC) , 38205 La Laguna, Tenerife , Spain 16 INAF - Osservatorio Astrofisico di Catania , via S. Sofia, 78, 95123 Catania , Italy 17 Instituto de Astrofísica de Andalucía-CSIC, Apdo. 3004, 18080 Granada , Spain 18 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto , Rua do Campo Alegre, 4169-007 Porto , Portugal 19 Centro de Astrofisica, Universidade do Porto , Rua das Estrelas, 4150-762 Porto , Portugal Context. Knowledge of the abundance distribution of star forming regions and young clusters is critical to investigate a variety of issues, from triggered star formation and chemical enrichment by nearby supernova explosions to the ability to form planetary systems. In spite of this, detailed abundance studies are currently available for relatively few regions. Aims. In this context, we present the analysis of the metallicity of the gamma Velorum cluster, based on the products distributed in the first internal release of the Gaia-ESO Survey. Methods. The gamma Velorum candidate members have been observed with FLAMES, using both UVES and Giraffe, depending on the target brightness and spectral type. In order to derive a solid metallicity determination for the cluster, membership of the observed stars must be first assessed. To this aim, we use several membership criteria including radial velocities, surface gravity estimates, and the detection of the photospheric lithium line. Results. Out of the 80 targets observed with UVES, we identify 14 high-probability members. We find that the metallicity of the cluster is slightly subsolar, with a mean [Fe/H] = −0.057 ± 0.018 dex. Although J08095427-4721419 is one of the high-probability members, its metallicity is significantly larger than the cluster average. We speculate about its origin as the result of recent accretion episodes of rocky bodies of ∼60 M⊕ hydrogen-depleted material from the circumstellar disk. - Based on observations collected at the ESO telescopes under programme 188.B3002, the Gaia-ESO large public spectroscopic survey. Full Tables 1–4 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A55 1. Introduction Open clusters are excellent tracers of the chemical pattern of the Galactic thin disk and its evolution (e.g., Friel 1995) . The youngest clusters, the so-called pre-main-sequence (PMS) clusters with ages 50 Myr, are of particular interest since they are still close to their birthplaces and contain a homogeneous stellar population that has not had time to disperse through the Galactic disk. Thus, they are key objects to trace the current chemical composition (...truncated)


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L. Spina, S. Randich, F. Palla, G. G. Sacco, L. Magrini, E. Franciosini, L. Morbidelli, L. Prisinzano, E. J. Alfaro, K. Biazzo, A. Frasca, J. I. González Hernández, S. G. Sousa, V. Adibekyan, E. Delgado-Mena, D. Montes, H. Tabernero, A. Klutsch, G. Gilmore, S. Feltzing, R. D. Jeffries, G. Micela, A. Vallenari, T. Bensby, A. Bragaglia, E. Flaccomio, S. Koposov, A. C. Lanzafame, E. Pancino, A. Recio-Blanco, R. Smiljanic, M. T. Costado, F. Damiani, V. Hill, A. Hourihane, P. Jofré, P. de Laverny, T. Masseron, C. Worley. The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum, Astronomy & Astrophysics, 2014, pp. A55, 567, DOI: 10.1051/0004-6361/201423527